SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Former ARCO Station #595 Page 2 of 3 6100 N. Highway 99 October 13, 2014 Stockton, CA 95212 • Completion of a leaching evaluation for potential future impacts to groundwater; and • Preparation and submittal of a report of findings that will include a summary of activities, results and recommendations. The EHD tentatively approves the (SAWP) submitted by Arcadis, contingent upon successful meeting the following EHD requirements: • Obtaining the required EHD permits for the soil vapor probes and borings, including access agreement for groundwater sampling of DW-1 R. • Sampling groundwater with proper technique. According to the EHD's Recommended Groundwater Sampling Guidelines, after the appropriate volume of purge water is removed and before a sample is collected, another DTW measurement should be taken and recorded. If the well has not recovered 80% of the original standing water in the well casing within a reasonable amount of time (<1 hour) a sample may be collected. The amount of recharge (final DTW) prior to sampling should be noted in the field notes. • According to San Joaquin County Well Standards, sealing material is not to exceed 5% bentonite. If the field technician cannot demonstrate to the field inspector that bentonite material does not exceed the 5% limit, sealing with neat cement would be an approved alternative. • The use of Teflon tubing for the construction of soil vapor probes will be the only EHD approved form of tubing. No substitutions will be made during field work activities. • Soil vapor sampling should be conducted according to the guidelines set from California Environmental Protection Agency. Please refer to Advisory Active Soil Gas Investigations, April 2012, for proper soil gas sampling procedure. • The use of 1-liter batch certified SUMMA canisters for collecting soil vapor samples will be the only EHD-approved containers. No substitutions will be made during field work activities. • A material blank is required along with a duplicate and equipment blank sample for soil vapor sampling. EiiD�vlll approve data demonstrating the use of a-materrjr"bT9rR-TrMTr a previous similar soil gas sampling event in lieu of providing a material-blank. • Investigation-derived waste (IDW) generated from field activities should be collected and placed in secure containers. IDW containers left onsite, must be completely identified with the proper labels (Hazardous/Non-Hazardous Material). A composite sample of the IDW may be collected to determine if waste is hazardous. • Notify EHD of all groundwater sampling events along with any permitted field activities at least 72 hours in advance of the scheduled event. • All water used for the purpose of abandonment of boreholes or construction of soil vapor probes must be potable water and not water that has been displaced from another non- potable source. With these conditions, the EHD approves the work plan as submitted.